Hurricanes and Tornadoes That Hit Derby, CT

The nearest NOAA station with 1991–2020 climate normals is New Haven Tweed Airport, CT, 11 miles east of Derby at 3 feet. July is the warmest, with an average high of 82°F and low of 66°F; January is the coolest, at 38°F and 23°F. April is the wettest at 4.2 inches of precipitation on average and January the driest at 2.7 inches; the year adds up to 41.8 inches over 74 days with at least a tenth of an inch. June to November, the hurricane season months, bring 51% of the year's precipitation (21.4 of 41.8 inches); the other six months are drier. September has brought the most of the 50 tropical systems that passed within 75 miles (22); a normal September there has highs of 75°F and 4.0 inches of precipitation. Highs reach 90°F on about 6 days a year, almost all from July to August. Lows fall below freezing on about 102 nights a year. That 41.8 inches is more than at 1 of the 27 Connecticut stations used on this site (4%). Ansonia, 1 mile north, has its own station (Mt Carmel, CT): 50.5 inches a year, 8.7 more than here, and a July average high of 85°F against 82°F.

Water temperature at the NOAA tide station New Haven, CT, 10 miles east, averaged 75°F in August and 37°F in February over 2021–2025. No month averaged 80°F. Sea level at the Bridgeport tide gauge, 11 miles from Derby, has risen 1.35 ± 0.08 inches per decade from 1964 to 2025, NOAA's linear trend; at that pace it is 13.5 inches in a hundred years. That is faster than at 81 of the 144 U.S. gauges with a NOAA trend.

Since 1996, the National Weather Service has logged 245 flood, rain, thunderstorm wind and lightning events that began within 10 miles of Derby: 151 thunderstorm wind reports, 76 flash floods, 10 lightning strikes and 8 floods. They killed 3 people and injured 10, and the NWS estimated $2.5 million in property and crop damage. The strongest thunderstorm gust on record here was 90 mph, on June 24, 2010. August has had the most flash floods, 26 of 76. Of the 186 Connecticut cities on this site with a flash flood on record, 182 have had fewer than Derby.

Flood insurance policyholders in Derby's ZIP code 06418 have filed 41 claims with the National Flood Insurance Program since 1978, and were paid $123,000 for buildings and contents, in the dollars of each year. The most came from Flooding in 1984: 10 claims (24% of all) and $28,000. 54% of the claims carry the name of a storm or flood event; the rest have no event name. Of the 128 Connecticut cities on this site with 10 or more claims, 53 have fewer than Derby.